From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F00991E1A3D for ; Fri, 14 Nov 2025 21:10:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763154641; cv=none; b=ZvvNc9Qc2pka5YHTlxF5yNe5TxN4j+PcXp52mX/J+iLzn967sGxgDPQnnDMPxrMEOeUYRWLv1YdTm4hb0FUirFDpWmF3F+vqGxYyJm8zctKJkEA26g82aN5n7eOeRopmEM0K81xhNNHHBobqbJPVhl81KEQt5f8uyZafOMEKC7s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763154641; c=relaxed/simple; bh=iMfC6oXUu1Tgqq9v3zVcdoBb9JXrBzY50ISUHFAcSvk=; h=Content-Type:MIME-Version:Subject:From:Message-Id:Date:References: In-Reply-To:To:Cc; b=NhjM+YiMQPc2/sEyn/iq/gufQMKD4ynXVaDE7F3gq9q8eWjOHymbf6KUcuxmfF9/HtVNQBhJUMiN+pB8177XST+Xr+rKqsVjPsVrksOCs0esEBanYdFYiQvJZ5w5im1r0yr0/e3xpz4t6HjfgazizOLMs8CWPK2gxC22IhU2fgA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tOoAkslk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tOoAkslk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70932C4CEF1; Fri, 14 Nov 2025 21:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763154640; bh=iMfC6oXUu1Tgqq9v3zVcdoBb9JXrBzY50ISUHFAcSvk=; h=Subject:From:Date:References:In-Reply-To:To:Cc:From; b=tOoAkslkR/nFfbMmU2TRbB9difi8zbc/0SZfUatCjTv8ZrDTXwAzfQayRhSKrCwE/ pJXOvHv3V8he37Syxuk1HVtGYLcyYBtbLf79EEEdssTxFIuzp+fgWX64WdnpL0EESu VLgNHmyUPqhP1zqpI4KvsHN+4pB6fgKGx65wOQlFmQIVqbJnBtWIx97UchsGGuEs9x 4Id6mYcQ3gx2wF2oV/GSLxtwA2O7x93z+f04sBQoSjgEn5xGNZyShu5XRJsjbrv2pa pp1TLENBAuCXxFMLEIk8znY99vOZrR8vO9VwExwKMwlI0pQ0weL8OwMbiFPZb/Zzxi SXBDSLUKq7W3w== Received: from [10.30.226.235] (localhost [IPv6:::1]) by aws-us-west-2-korg-oddjob-rhel9-1.codeaurora.org (Postfix) with ESMTP id 33AEB3A78A5E; Fri, 14 Nov 2025 21:10:10 +0000 (UTC) Content-Type: text/plain; charset="utf-8" Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH bpf-next v3] bpf: prevent nesting overflow in bpf_try_get_buffers From: patchwork-bot+netdevbpf@kernel.org Message-Id: <176315460900.1836273.4880914220928458994.git-patchwork-notify@kernel.org> Date: Fri, 14 Nov 2025 21:10:09 +0000 References: <20251114064922.11650-1-chandna.sahil@gmail.com> In-Reply-To: <20251114064922.11650-1-chandna.sahil@gmail.com> To: Sahil Chandna Cc: yonghong.song@linux.dev, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, bigeasy@linutronix.de, bpf@vger.kernel.org, syzbot+b0cff308140f79a9c4cb@syzkaller.appspotmail.com Hello: This patch was applied to bpf/bpf-next.git (master) by Alexei Starovoitov : On Fri, 14 Nov 2025 12:19:22 +0530 you wrote: > bpf_try_get_buffers() returns one of multiple per-CPU buffers based on a > per-CPU nesting counter. This mechanism expects that buffers are not > endlessly acquired before being returned. migrate_disable() ensures that a > task remains on the same CPU, but it does not prevent the task from being > preempted by another task on that CPU. > > Without disabled preemption, a task may be preempted while holding a > buffer, allowing another task to run on same CPU and acquire an > additional buffer. Several such preemptions can cause the per-CPU > nest counter to exceed MAX_BPRINTF_NEST_LEVEL and trigger the warning in > bpf_try_get_buffers(). Adding preempt_disable()/preempt_enable() around > buffer acquisition and release prevents this task preemption and > preserves the intended bounded nesting behavior. > > [...] Here is the summary with links: - [bpf-next,v3] bpf: prevent nesting overflow in bpf_try_get_buffers https://git.kernel.org/bpf/bpf-next/c/c1da3df7191f You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html